As is well known to those skilled in the art, middle distillate fuels typified by diesel oil, Avjet fuel, fuel oils, kerosene, etc may be stored for extended periods of time under unfavorable conditions which are conducive to formation of solid deposits. These deposits, which are produced during storage at room temperature in the presence of air, accumulate on strainers, filters, screens etc. with which the oil comes into contact and ultimately plug the openings with resultant problems in operation.
The propensity of a system to form a deposit may be determined by ASTM Test D-2274 which provides indication of oxidative deterioration or stability cf a fuel. In the Potential Deposit (PDT) Test, comparable indications are obtained under more severe conditions. In this latter test a test specimen of oil is subjected to contact with air at elevated temperature; and after 2 hours, the turbidity of the specimen is determined on a scale of 1-4. A rating of 1 or 2 is satisfactory and a rating of 3 or 4 is unsatisfactory.
Background for the instant invention may be obtained from numerous patents including U.S. Pat. Nos. 4,548,724; 533,361; etc.
It is an object of this invention to provide an improved middle distillate fuel composition characterized by improved performance as determined by the Potential Deposit Test. Other objects will be apparent to those skilled in the art.